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Re: Incorrect DFA scheduling of output dependency.
- From: Steven Bosscher <stevenb at suse dot de>
- To: Daniel Towner <daniel dot towner at picochip dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Mon, 6 Dec 2004 13:30:40 +0100 (CET)
- Subject: Re: Incorrect DFA scheduling of output dependency.
- Organization: SuSE Linux AG
- References: <41B442B7.9020408@picochip.com>
On Dec 06, 2004 12:29 PM, Daniel Towner <daniel.towner@picochip.com> wrote:
> Any ideas?
You're not making this easy because you haven't told anything about:
1) what target you're working on (apparently something that is not
in the FSF GCC tree);
2) what your DFA description looks like (did you tell the scheduler
that those two instructions are issued in parallel?); and
3) what version of GCC you are working with.
Anyway, I'll assume you work from mainline. If you use a recent
snapshot: There was a bug last week where REG notes were being
removed in pairs when they shouldn't. That bug had been there for
about two weeks. Perhaps your REG_DEP_OUTPUT note was incorrectly
being removed. In that case, try a newer shapshot.
But first look at the scheduler dumps (-dS and -dR) to see if the
output dependency is there, of course...
Gr.
Steven